重组变异体二氢叶酸还原酶和绿色荧光蛋白腺相关病毒载体的构建及外源基因表达

Construction of Adeno-Associated Virus Vector Carried Mutated Dihydrofolate Reductase and Green Fluorescent Protein and Its Expression in NIH3T3 Cells

构建携带变异体二氢叶酸还原酶 (mDHFR)和绿色荧光蛋白 (GFP)融合基因的重组腺相关病毒 (AAV)载体 ,并使其在NIH3T3细胞中表达 ,观察NIH3T3细胞的耐药性变化。先分别扩增mDHFR和GFP基因片段 ,并用甘氨酸接头以PCR的方法将其连接在一起 ,插入T载体 ,酶切后插入AAV载体 ,包装成病毒后感染NIH3T3细胞 ,通过PCR、荧光显微镜和流式细胞术对融合基因的表达进行观察。结果 :PCR检测到NIH3T3细胞DNA基因组中mDHFR和GFPcDNA ,荧光显微镜和流式细胞仪观察到绿色荧光蛋白表达的比率约为 2 5 % ,MTT法检测转基因组对MTX的耐药性增强。结论 :AAV载体可以将mDHFR和GFP融合基因导入NIH3T3细胞并成功表达 ,使其对MTX的耐药性增强 。

The aim of this study was to construct recombinant mDHFR GFP/AAV vector containing mutated dihydrofolate redutase(mDHFR) and green fluorescent protein(GFP) fusion genes and its expression in NIH3T3 cells, to investigate the resistance of the cells to methotrexate. Amplified cDNA of mDHFR and GFP segmented from their plasmid separately were linked by PCR with the aminoacetic acid linker. The fusion gene was inserted into T vector, and after enzyme cutting the fusion gene fragment was inserted into AAV vector, then packaging the vector into recombined AAV and infected NIH3T3 cells. Expression of gene fusion was observed by PCR, fluorescent microscopy and flow cytometry. mDHFR and GFP cDNA were found in NIH3T3 genomic DNA, the GFP expression rate was about 25%, and resistance of the transfered cells to MTX was increased markedly. The results showed that AAV vector can transfer mDHFR and GFP fusion gene into NIH3T3 cells and increase resistance to MTX in gene modified cells. This data provided a basis for application of mDHFR and AAV vector in gene therapy.